% radon flux

%The potential of radon as a tracer for transport and mixing is often 
%limited by a poor description of
%its surface flux density. Mechanistic understanding of radon flux is combined
%with field measurements to turn continental scale soil and radiometric data into a best
%estimate of surface radon flux density distribution in space and time.

 

%The ability of ionizing radiation to produce condensation nuclei aerosols in filtered air is
%well known. Recent studies have indicated that radiolysis results initially in the production of highly
%diffusive, nanometer-sized (< 2 nm) clusters. Aerosols in the 1-10 nm range are also produced by other
%processes mostly involving nucleation, e.g. for purposes of materials synthesis. Radiolytic nuclei can
%be formed by the binary ion-induced nucleation of the precursor vapors, such as sulfuric acid and
%water; ultrafine particles (> 5 nm) can then evolve by coagulation and growth processes

%The addition of SO2 to a humidified radon-air mixture for certain conditions is
%known to result in the formation of ultrafine sulfuric acid aerosols through radiolytic
%oxidation, followed by nucleation and ultrafine particle formation.

%The hydroxyl
%radical from water molecule radiolysis is a key element to the
%particle formation mechanism


%Compared with atmospheric aerosol particles (radius range from 10nm to 10um), 
%atmospheric ions are much smaller. 
%
%In the free atmosphere, the rate of production of small ions is in balance with the rate
%of neutralisation by recombination and the rate of attachment to condensation nuclei.
%
 
% why we study ion production and ip by radon ...   

%\citep{israel:1971}.
%Due to the spacial distribution of the Earth's magnetic field, 
%the cosmic ionization rate is smaller near tropical regions while 
%larger near the polar regions. 
%Furthermore, ionization caused by cosmic rays varies with altitude, with a maximum 
%in the upper atmosphere.


%comprising approximately 20\% of surface ionization rate but it's distribution varies with altitude.(2) So,
%air-ion generation near the ground varies with radon concentration. 


%which splits the electron from the molecule and makes the original molecule with
%positive charge.  


%Alpha decay carries away positive charge and electrons are stripped from the parent atom by
%its recoil. Therefore, the decay products are formed as positive ions. Air is ionised by radiation
%from the naturally occurring radionuclides in the air and on the ground and by cosmic rays.
%Production of one ion pair requires 32.5 eV if ionisation is caused by fast electrons, 35.6 eV
%if by alpha particles. The total energy dissipated in air per decay of radon depends on the
%equilibrium ratio of the radon decay products.
%In the free atmosphere, the rate of production of small ions is in balance with the rate
%of neutralisation by recombination and the rate of attachment to condensation nuclei.

%When a radioactive nuclide decays, electrons are stripped from the parent atom by its recoil
%and decay products are formed as positive ions. These ions can attract liquid and even solid
%material, thus forming clusters of atoms or particles in the submicron region ranging from
%0.001 to 0.01 ÎŒm. Air is permanently ionised by radiation from the natural radioactivity of air
%and by cosmic radiation which consists mostly of positively charged particles, 85% protons,
%10% alpha particles with a smaller percentage of positively charged stripped nuclei of heavier
%elements, such as Fe, Co and Ni, etc. Production of an ion pair requires 35.6 eV if ionisation
%is by alpha particles and 32.5 eV if by fast electrons. In the free atmosphere, the rate of
%production of small ions is in balance with the rate of neutralisation by recombination and the
%rate of attachment to condensation nuclei. Condensation nuclei are mostly the Aitken nuclei,
%which are submicrometre particles in the range 0.005 to 0.01 ÎŒm.

%Galactic cosmic rays (GCR) are a major source of ions in the troposphere (Bazilevskaya et
%al. 2008): upon entering the Earth atmosphere, primary cosmic ray particles, mostly hydrogen
%and helium nuclei, collide with atmospheric gas molecules and initiate a cascade of nuclear
%and electromagnetic reactions producing secondary cosmic rays. Due to the shape and
%orientation of the Earth's magnetic field, the GCR ionization rate increases from the magnetic
%equator towards the poles; its altitude profile has a peak in the upper troposphere/lower
%stratosphere. The GCR intensity and ionization rate are anti-correlated with the decadal solar
%cycle (Forbush 1954; Neher and Forbush 1958). A second important source of ionization
%in the troposphere is the radioactive decay of radon effusing from rocks and soils (Laakso
%et al. 2004b, and references therein). This source of ionization is strongest near the surface
%and in the boundary layer, and is not known to correlate with the solar cycle.



% wiki
% An ion is an atom or molecule where the total number of electrons 
% is not equal to the total number of protons, giving it a net 
% positive or negative electrical charge.

%Atmospheric ions are frequently classified into large ions (r > 3 nm), intermediate ions
%(1 > r > 3 nm), and small ions which are typically 0.5 nm in radius. Large ions are often classified as
%charged aerosol particles and have a distribution of electrical charges, whereas intermediate and small
%ions have unit charge. (e.g. Horrak et al, 2000)
%
%Atmospheric small ions are small molecular clusters carrying a net electric charge.
%They are produced by ionisation of molecules in the air, and these initial ions are
%quickly clustered by water molecules to produce a central, singly charged, ion
%surrounded by 4-10 water molecules. Air ions exist at typical ground level
%concentrations over land of, on average, a few hundred per cubic centimetre. They are
%subject to considerable variability from atmospheric turbulence and transport effects.
%This influences the ion concentration both directly and indirectly via the aerosol
%population, as identified by Rutherford (1897).

 


%\citep{israel:1971}.  


% radon ion 

%Radon description

%The natural radionuclide uranium-238 in Earth's crust,
%As an intermediate in the
%decay chain of uranium-238 formed on radium-226, the radioactive gas

